I'm quite familiar with this speaker as it is my only main system speaker and I bought them new from Fat Julian's audio in 1984! A peerless imager, they have a very smooth response, good low level detail and excellent off axis performance. The drivers consist of the following: Seas 8" cone driver in a forward firing ported enclosure, a 2" Dynaudio dome midrange, flanked by two Vifa 3/4" soft dome tweeters @45 degree angles, and finally at the top a 1" Vifa soft dome tweeter. The dome drivers are mounted in an open architecture. Crossover is quasi 2nd order with crossover points of 950Hz and 2.5KHz. Sensitivity is listed as 86db, but the relatively benign phase angle makes easy to drive. I have a list of the driver model #'s and would be happy to list them if you need replacements, (assuming they're still being manufactured).